Tool for boring breech-loading ordnance



(No Model.)

G. GERDOM. TOOL FOR BORING BREEOH LOADING ORDN-ANOB. No. 481,300.Patented Aug. 23,1892

Fie.5. FIG-6.

WITNESSES; a I INVENTORZ BY Gnsso w Gsnnow JIfiTm-ney.

NITED STATES ATENT FFICE.

GREGORY GERDOM, OF WVEST TROY, ASSIGNOR OF ONE-HALF TO JOHN H. REYNOLDS,OF TROY, NEWV YORK.

TOOL FOR BORING BREECH-LOADING ORDNANCE.

SPECIFICATION forming part of Letters Patent No. 481,300, dated August23, 1892.

Application filed February 27, 1892. Serial No. 422,993. (No model.)

To all whom it may concern:

Be it known that I, GREGORY GERDOM, of West Troy, in the county ofAlbany and State of New York, have invented new and useful Improvementsin Tools for Boring Breech- Loading Ordnance, of which the following isa full and specific description, reference being had to the accompanyingdrawings, which form part of this specification, and in which Figure 1is-a side elevation of my cutterhead embodying the improvements hereinset forth. Fig. 2 is an end elevation of the foremost end of the same.Fig. 8 is a plan view. Fig. 4 is a side elevation of said cutter-headwith the cheek-blocks removed therefrom. Fig. 5 is an enlarged sideelevation of one of my improved form of cutters detached from thecutter-head, the angular cutting-edges of the cutter being shown in anexaggerated form; and Fig. 6 is an end elevation of the same.

This invention relates to improvements on the boring-tool for whichLetters Patent of the United States No. 466,869 were granted to meJanuary12, 1892; and the object of this improvement is to render saidboring-tool more eifective in its operation and to provide facilitiesfor discharging the chips produced by the cutters into the bore of thecannon'in advance of the boring-tool.

As illustrated in the drawings, A designates the cutter-head, which Ipreferably make of cast metal and provide it with a shank 1 or othersuitable means for attaching said outter-head to the foremost end of aboring-bar of the form usually employed for boring breech-loadingordnance. Said cutter-head is provided with a cylindrical body 2 of asmaller diameter than the bore of the cannon on which it is used, andsaid shank should project centrally from the rearmost end of saidcylindrical body when such means of attachment is employed. A flattenedmember 3 extends longitudinally from the foremost end of saidcylindrical body and has its opposite plane faces each provided with a1ongitudinal tongue 4, for a purpose hereinafter explained. The foremostend of the flattened member is provided with recesses 5 for receivingthe detachable cutters for said outter-head, one of said recesses beingform ed in each plane face at opposite edges of said flattened memberand so that the back of each recess will range substantially on the samediametrical center line of said cutter-head. The arrangement of saidrecesses in respect to the plane faces and edges of the flattened member3 of said cutter-head is shown in Fig. 2.

B designates the cutters of my boring-tool. Said cutters are made ofsteel in the form of flat plates, which after being properly shaped areproperly tempered for effecting the cutting away of the metal in theprocess of boring the cannon. The part 6 is designed to efiect thefinishing of the bore of the cannon in such manner that no spiral creasewill be left in the bore by reason of a sharp corner at the rearmostedge of said cutter. It is made parallel to the center line of thecutter-head A and of such width that the required caliber of said borewill be obtained. Immediately in advance of said part aslightly-inclined cutting-edge 7 is joined to the part 6, and inpractice I find that an inclination of seventy-five ten-thousandths ofan inch to one inch in length gives a good result in said inclinedcutting-edge. Immediately in advance of the inclined cutting-edge 7another inclined cutting edge 8 of greater angularity is joined to thecutting-edge 7. The foremost end of the cutting-edge 8 requires to bemade so that the foremost end of the boring-tool will be small enough toallow that part to enter the preliminary bore of the cannon with perfectfreedom. The inclination of the cutting-edge 8 is preferably made aboutone-eighth of an inch in a length of one and one-half inches from a lineranging with the cutting-edge 7. The parts 6, 7, and 8 form thecutting-edge of my cutters, and they form a continuous line. A groove orcutter 9 is formed in the face of each cutter to follow the shape ofsaid cutting-edges, and thereby a sharp cutting-edge is produced topositively cut the metal to effect a smooth and uniform bore in thecannon. The part 8 will remove the greater part of the metal, the part 7skims off a slight chip to produce the required caliber, and the part- 6Will remove all trace of a spiral groove that might possibly be formedby feeding the cutter-head inward into the bore of the cannon.Immediately following the part 6 the cutter B is reduced, as at 10,

to prevent that part from bearing against the bore of the cannon toeffect a possible damage to said bore. Each of said cutters is securedin 1ts appropriate recess 5 of the cutter-head A by means of bolts 11,which pass through boltholes 12, which are slotted, as shown in Fig.5,to allow said cutters to be adjusted inwardly and outwardly in respectto the longitudinal center line of the cutter-head.

O designates the cheek-blocks of my boringtool, which are preferablymade of wood in the form of a segment of a cylinder. Said cheek-blocksare seen red to the opposite plane faces of the flattened member 3 ofthe cutterhead by means of bolts 13, which are inserted in counterboredbolt-holes 14, so as to keep said bolts below the cylindrical surface ofthe cheek-blocks, and the plane faces of the latter are each providedwith a longitudinal groove that is fitted to engage snugly with a tongueet of the cutter-head 13, so as to retain the cheek-blocks in animmovable position on said cutter-head. \Vhen said checkblocks aresecured to said cutter-head, they should be turned off in a lathe, sothat their diameter will exactly correspond to the finished bore of thecannon on which the boring-tool is to be used. The foremost end of eachcheek-block should be beveled backward, as at 15, at the side of thecutter B whereon the cutting-edge is formed, and said bevel should becarried backward to about the rearmost termination of the part 0 of thecorresponding cutter, and thereby provision is made for discharging thechips from the cutters B into the bore of the cannon in advance of theforemost end of the boring-tool.

My boring-tool is specially designed for boring breech-loading ordnancemade from steel or iron forgings and in which a preliminary bore hasbeen made of smaller diameter than the finished bore of the cannon. Saidpreliminary bore must extend entirely through the length of the forgingand should be slightly larger than the smaller end of the boring-tool.

This invention operates differently from the boring-tool described inthe Letters Patent hereinbefore referred to, for the reason that thelatter increased the diameter of the preliminary here to that of thefinished bore at once by a single inclined cut, while my presentinvention effects the enlargement progressively, and thereby the duty ofthe outting-edge 6 in finishing the bore is reduced, for the reason thatthe cutting-edge 7 leaves but a small thickness of metal to be removedby the cutting-edge 6, and as a result the finished bore is completed ina much more perfeet manner, as is required by the character of the useto which the cannon is to be put. In addition to the foregoingdifference, the cheelcblocks C, by reason of their beveled portion attheir foremost end, remove the borings from the way of the boring-toolinstead of allowing said borings to crowd in between the periphery ofthe check-blocks and the bore of the cannon, thereby remedying a defectcommon to boring-tools whose cheek-blocks have a foremost end formedperpendicularly to the longitudinal line of their sides \Vhat I claim asmy invention, and desire to secure by Letters Patent, is-

1. In a tool for boring ordnance, a cutter having a cutting'edge whichat its foremost end is formed at an inclination to the central axis ofsaid tool, a succeeding cutting-edge of slighter angularity to saidaxis,and a final or finishing cutting-edge which is parallel to saidaxis, all of said cutting-edges being connected continuously, as and forthe purpose herein specified.

2. In a tool for boring ordnance, a cutter having a cutting-edge whichat its foremost end is formed at an inclination to the central axis ofsaid tool, a succeeding cutting-edge of slighter angularity to saidaxis, and a final or finishing cutting-edge which is parallel to saidaxis, all of said cutting-edges being connected continuously and havingthe form of a sharp lip, which is produced by a groove or gutter formedin the face of the cutter, as and for the purpose herein specified.

In a tool for boring ordnance, the combin ation of a cutter-headprovided with a flattened member 3, provided with a longitudinal tongue4: on each of its plane faces and recesses 5 for receiving removablecutters, said recesses being formed in opposite faces of said flattenedmember at diametrically-opposite edges of the same, removable cutters B,secured in said recesses, and segmental cheek-blocks O, secured toopposite faces of said flattened member and forming complementaryadditions thereto that will exactly fit into the finished bore of thecannon to retain the boring-tool in a true position in said bore, theforemost end of each cheek-block being beveled rearwardly, as at 15, forthe purpose of displacing the chips of metal from the path of saidboring-tool, as herein specified.

GREGORY GERDOM.

\Vitnesses:

WM. II. Low, S. B. BREW'ER.

